Yu Han, Xie Jian, Shu Na, Pan Fei, Ye Jianglin, Wang Xinyuan, Yuan Hong, Zhu Yanwu
Hefei National Research Center for Physical Sciences at the Microscale and Department of Materials Science and Engineering and CAS Key Laboratory of Materials for Energy Conversion, University of Science and Technology of China, Hefei, Anhui 230026, China.
iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), University of Science and Technology of China, Hefei, Anhui 230026, China.
Research (Wash D C). 2019 Sep 15;2019:9129457. doi: 10.34133/2019/9129457. eCollection 2019.
The lithium (Li) metal is one promising anode for next generation high-energy-density batteries, but the large stress fluctuation and the nonuniform Li deposition upon cycling result in a highly unstable interface of the Li anode. Herein, a simple yet facile engineering of the elastic interface on the Li metal anodes is designed by inserting a melamine sponge between Li and the separator. Driven by the good elasticity of the sponge, the modified Li anode maintains a Coulombic efficiency of 98.8% for 60 cycles and is cyclable at 10 mA cm for 250 cycles, both with a high capacity of 10 mA h cm. We demonstrate that the sponge can be used to replace the conventional polypropylene as a porous yet elastic separator, showing superior cycling and rate performance as well. In addition to the efficiency of the elastic interface on the cycling stability, which is further confirmed by an in situ compression-electrochemistry measurement, the porous structure and polar groups of the sponge demonstrate an ability of regulating the transport of Li ions, leading to a uniform deposition of Li and the suppression of Li dendrites in cycling.
锂（Li）金属是下一代高能量密度电池颇具前景的阳极材料，但循环过程中较大的应力波动和不均匀的锂沉积会导致锂阳极界面高度不稳定。在此，通过在锂与隔膜之间插入三聚氰胺海绵，设计了一种简单易行的锂金属阳极弹性界面工程。在海绵良好弹性的驱动下，改性锂阳极在60次循环中保持98.8%的库仑效率，在10 mA cm下可循环250次，两者均具有10 mA h cm的高容量。我们证明，该海绵可用于替代传统的聚丙烯作为多孔且有弹性的隔膜，也表现出优异的循环和倍率性能。除了弹性界面在循环稳定性方面的效率通过原位压缩电化学测量得到进一步证实外，海绵的多孔结构和极性基团还显示出调节锂离子传输的能力，从而导致锂的均匀沉积并抑制循环中的锂枝晶。
